Triad Omnisub blows fuses

I have an old Omnisub 8 mini.
It blew a fuse, tried replacing it and it blows gain immediately.
I can see nothing obviously burnt and the caps seem OK.

Could it be one or both of the IRF 730 Mosfets on the power supply?
I tried testing them in circuit and they both show a short between the D and S pins.
G and S shows short on one of them but not on the other. You can see the two of them towards the top of the picture attached to the heat-sink

I suppose the only proper way to check them would to first desolder them from the PCB but just looking for a little direction before hauling out the soldering iron.


atriad by streak3, on Flickr